It's being reported that the new writer for Dawn Treader is Michael Petroni.
I'm concerned to note that nothing in his portfolio demonstrates the Australian writer's ability to do Lewis any kind of justice, to put it kindly. I've been unable to find any interviews or other insight as to his own worldview. (I've actually sat on this awhile, hoping more would come out on him — but, not yet.)
Good news, though: they're looking for a 2010 release date.